猿类胰腺的动脉分布模式初步研究

目的:对25例猿类胰腺及周围动脉进行解剖分析,研究猿类胰腺动脉的起源及肠系膜上动脉和腹腔干动脉的吻合关系。方法:对6例类人猿(Gorilla 1例,Pan troglodytes 3例和Hylobates lar 2例),13例狭鼻猿(Papio hamadryas 1例,Papio anubis 2例和Cercopithecus aethiops 10例)和6例阔鼻猿(Saimiri 6例)处死后取出内脏,用10%的福尔马林固定后储存在50%的酒精中,对胰腺、胃及脾脏的供应血管进行解剖游离和解剖分析,最后进行画图。结果:猿类胰腺动脉分布发源自腹腔干和/或肠系膜上动脉,胰腺接受腹腔干及肠系膜动脉的双向供应外,也有独自接受腹腔干动脉的血供,腹腔干动脉与肠系膜上动脉之间无任何吻合支存在者占总数的32%。结论:猿类胰腺形态与人类相似,其动脉分布来源比人类更有多样性。     

Protein secretion in Corynebacterium glutamicum

Corynebacterium glutamicum, a Gram-positive bacterium, has been widely used for the industrial production of amino acids, such as glutamate and lysine, for decades. Due to several characteristics – its ability to secrete properly folded and functional target proteins into culture broth, its low levels of endogenous extracellular proteins and its lack of detectable extracellular hydrolytic enzyme activity – C. glutamicum is also a very favorable host cell for the secretory production of heterologous proteins, important enzymes, and pharmaceutical proteins. The target proteins are secreted into the culture medium, which has attractive advantages over the manufacturing process for inclusion of body expression – the simplified downstream purification process. The secretory process of proteins is complicated and energy consuming. There are two major secretory pathways in C. glutamicum, the Sec pathway and the Tat pathway, both have specific signal peptides that mediate the secretion of the target proteins. In the present review, we critically discuss recent progress in the secretory production of heterologous proteins and examine in depth the mechanisms of the protein translocation process in C. glutamicum. Some successful case studies of actual applications of this secretory expression host are also evaluated. Finally, the existing issues and solutions in using C. glutamicum as a host of secretory proteins are specifically addressed.     

5种沙拐枣的水分生理特征比较

在野外和室内观测5种沙拐枣的生物生态特征及其水分生理指标。结果表明:白皮沙拐枣和新疆沙拐枣以大蒸腾,较强的持水力,保持较高的束缚水来抵抗干旱;乔木状沙拐枣则以较强持水力,最低限度的蒸腾强度抵抗干旱。综合指标分析表明:白皮沙拐枣和乔木状沙拐枣的耐旱性较强,新疆沙拐枣和红皮沙拐枣次之,小果沙拐枣的耐旱性最弱;抗风蚀能力由强至弱为:红皮沙拐枣>新疆沙拐枣>小果沙拐枣>白皮沙拐枣>乔木状沙拐枣。4h为5种沙拐枣失水的拐点,因此,在进行植苗造林中,最好在起苗后4h内栽植,以提高造林成活率。     

Sedimentary nitrogen uptake and assimilation in the temperate zooxanthellate sea anemone Anthopleura aureoradiata

The sea anemone Anthopleura aureoradiata (Carlgren), which harbours symbiotic dinoflagellates (zooxanthellae), is abundant on mudflats and rocky shores around New Zealand. We measured the potential for particulate nitrogen uptake from sediment by A. aureoradiata and the subsequent consequences of this uptake on the nitrogen status of its zooxanthellae. Sediment was rinsed, labelled with (¹⁵NH₄)₂SO₄, and provided to anemones at low (0.23 g ml^− 1) and high (1.33 g ml^− 1) sediment loads for 6 h. Both anemone tissues and zooxanthellae became enriched with ¹⁵N. Enrichment of anemone tissues was similar at both high and low sediment loads, but the zooxanthellae became more enriched at the lower load. This was presumably because the uptake of ammonium, arising from host catabolism, by zooxanthellae is light driven and because the anemones at the lower load were able to extend their tentacles into the light while those at the higher load were not. The influence of sediment uptake on the nitrogen status of the zooxanthellae was determined by measuring the extent to which 20 μM NH₄⁺ enhanced the rate of zooxanthellar dark carbon fixation above that seen in filtered seawater (FSW) alone; the ammonium enhancement ratio (AER) was expressed as [dark NH₄⁺ rate/dark FSW rate], where ‘rate’ refers to C fixation and a ratio of 1.0 or less indicates nitrogen sufficiency. When anemones were starved with and without rinsed sediment in nitrogen-free artificial seawater for 8 weeks, zooxanthellar nitrogen deficiency became apparent at 2-4 weeks and reached similar levels in both treatments (AER = ~ 2). In contrast, anemones fed 5 times per week for 8 weeks with Artemia nauplii were nitrogen sufficient (AER = 1.03). In the field, zooxanthellae from mudflat anemones were largely nitrogen sufficient (AER = 1.26), while nitrogen deficient zooxanthellae were present in anemones from a rocky intertidal site (AER = 2.93). These results suggest that, while there was evidence for particulate nitrogen uptake, dissolved inorganic nitrogen (especially ammonium) in interstitial pore water may be a more important source of nitrogen for the zooxanthellae in mudflat anemones, and may explain the marked difference in nitrogen status between the mudflat and rocky shore populations.     

斐豹蛱蝶的繁殖生物学研究

在重庆进行了斐豹蛱蝶Argyreus hyperbius(L.)室内饲养和繁殖生物学研究。在自然光照条件下,室内温度22～25℃,相对湿度50%～80%,成虫喂10%的蜂蜜溶液,幼虫食堇菜科的植物,在此条件下,可进行自然交配、产卵;幼虫在盒内能正常生长发育并化蛹、羽化;同时在自然变温条件下,对斐豹蛱蝶蛹的发育起点温度和有效积温进行了研究,结果表明,发育起点温度为(14.10±0.19)℃,有效积温为68.33日·度。     

天山一号冰川表面冰尘和底部沉积层中可培养酵母菌系统发育类群的分布及生态生理特征

【目的】揭示乌鲁木齐河源天山1号冰川表面冰尘(CS)和底部沉积层(DS)可培养酵母菌系统发育类群及其结构组成差异,分析低温酵母菌代表菌株之间的生态、生理生化特性。【方法】利用4种培养基分离天山1号冰川可培养酵母菌,采用ITS基因序列分析确定菌种的系统进化地位。对分离菌株的最适生长温度、耐盐性和产酶等生态、生理学特性进行分析。【结果】从冰尘和底部沉积层中共分离出152株酵母菌菌株,通过ITSrRNA基因序列的NCBI比对和Rep-PCR指纹分型,结果表明酵母菌类群包括担子菌门(Basidiomycota)和子囊菌(Ascomycota),分属于14个属26种,其中担子菌门柄锈菌亚门(Pucciniomycotina)88株、伞菌亚门(Agariomycotina)24株,子囊菌门40株,冰川广布酵母菌Vishniacozyma victoriae为优势菌株(占比21.84%)。17种酵母的最适生长温度为15°C、2种为10°C、6种为20°C。25株代表酵母菌株产酶分析显示,产脂肪酶、淀粉酶、蛋白酶菌株分别为11株、11株、5株,6株3种酶都不产。【结论】天山1号冰川冰尘及底部沉积层可培养低温酵母系统发育类群结构存在差异,产低温酶活性高、稳定性好,为今后冰川低温酵母菌的研究提供有价值的数据支持。     

智力水平还是文化表现?——尼安德特人与现代人文化精致程度差异研究述评

尼安德特人和解剖学意义上的现代人在文化精致程度上的区别已经争论了很长时间,考古学者希望能得出一个确定的答案,两个假设应运而生:智力水平(尼人不能发展出精致的文化)与文化表现(尼人不需要发展出精致程度较高的文化)。古人类与考古材料显示智力水平假设有缺陷:尼人的基因进入了现代人的基因库中,而且他们有能力学习现代人的技术,在"过渡工业"的材料中可以找到相关证据;与此同时,至今还未找到关系到智力水平的大脑结构证据证明尼人智力水平不如现代人。检验文化表现假设的前提是尼人与早期现代人在智力水平上没有差异,却呈现出不同的社会网络和社会组织。本文在讨论尼人与现代人人口与社会交流的基础上,认为现代人复杂的社会组织切割了尼人的生活环境,同时火山爆发引起了资源短缺,最终导致了尼人在欧洲灭绝。     

基于空间优先级的快速城市化地区绿色基础设施网络构建——以南京市浦口区为例

绿色基础设施是一个由自然区域和其他开放空间相互联系的网络。在城市空间极为有限的情况下,如何有效构建城市绿色基础设施网络并识别那些具关键性景观生态功能的网络要素显得极为重要。为了给城市绿色基础设施网络的建设和管理提供新的建模与分析理念,以快速城市化的南京市浦口区为例,采用MSPA方法并结合景观连通性指数,遴选出了对维持景观连通性贡献最大的生境斑块作为绿色基础设施网络的网络中心,进而采用最小路径方法构建了研究区潜在的绿色基础设施网络,并尝试利用空间句法分析,基于结构优化视角对绿色基础设施网络进行优先级的识别,从而使绿色基础设施网络的构建更科学。研究结果可为快速城市化地区绿色基础设施网络的构建提供一种研究思路与方法,对绿色基础设施网络要素的优先级评价也具有一定的借鉴意义。     

广谱抗真菌转基因水稻植株化学成分与结构动态变化

【背景】种植广谱抗真菌水稻可能会带来一定的环境生物安全问题,对其植株的化学成分进行实质等同性分析是转基因水稻安全性评价的重要内容之一。【方法】以表达广谱抗真菌蛋白转基因水稻转品1和转品8及其相应非转基因水稻七丝软粘的秸秆为研究材料,采用化学法和扫描电镜技术分析外源基因的导入对水稻秸秆化学成分以及组织显微结构的影响。【结果】（1）在整个生长发育过程中,广谱抗真菌转基因水稻转品1和转品8与其非转基因水稻七丝软粘叶片、叶鞘和茎的纤维素、半纤维素、木质素以及粗蛋白含量的变化趋势基本一致,且品种间化学成分的含量不存在显著差异。（2）广谱抗真菌转基因水稻叶片表皮的硅质瘤状结构以及气孔的形状和致密程度与其非转基因水稻七丝软粘相似;茎壁、厚壁组织、薄壁组织以及大小维管束的形态和分布情况未发生明显变化。【结论与意义】表达广谱抗真菌蛋白转基因水稻秸秆的化学成分和组织显微结构与非转基因水稻基本一致。这为广谱抗真菌转基因水稻的环境安全性评估提供了依据。